Role of chicken TL1A on inflammatory responses and partial characterization of its receptor.

The role of chicken TNF-like ligand 1A (ChTL1A) on inflammation and its receptor candidates was investigated to further understand its function as a proinflammatory cytokine. ChTL1A decreased the viability of CHO-K1 cells transfected with chicken TNFR2 or decoy receptor 3 and bound to TNFR2 and decoy receptor 3. ChTL1A was detected in chicken blood samples taken 4 h after LPS injection. Increased mRNA for inflammatory response-related factors such as IL-1beta, IL-6, ChTL1A, IFN-gamma, inducible NO synthase, and cyclooxygenase 2 were found in spleen samples following LPS injection. Ceruloplasmin and alpha(1) acid glycoprotein (as positive acute phase proteins) were increased in chicken plasma 12 h after ChTL1A injection. The injection of anti-ChTL1A Ab was able to prevent typical increases in plasma nitrite plus nitrate, ceruloplasmin, and alpha(1) acid glycoprotein concentrations following LPS injection. These results indicate that ChTL1A is a proinflammatory cytokine in chickens, animals that do not have TNF-alpha and lymphotoxin alpha orthologous genes, and that its proinflammatory action is, at least in part, expressed through binding to TNFR2.